Make FDC3 conformance test framework run under CI as a contribution test

## Enhancement Request

### Use Case

The FDC3 Conformance tests are currently run manually in web browser. The test runner should be adapted or augmented such that it can run under a CI system, both for FDC3 development the development of other Desktop Agents, including FDC3 Sail).

This is likely to require an automated testing framework such as Playwright or Cypress to achieve as it needs to run within the scope of the browser. We could either use the existing runner or setup an alternative runner for CI use cases, as long as it runs the same tests (NOT including the manual tests).

One challenge may be that additional tabs need to open during the tests. However, its currently only the parent (runner) frame that needs to be interacted with. The FDC3 reference implementation can now pass the tests using iframes with the runner in one of those iframes, but this may not apply for other aggents, so ideally whatever is used to execute the test should support multiple windows.

Start by reading the existing FDC3 Conformance test runner and identify which tests are manual and which should run in CI. Evaluate an automated browser framework such as Playwright or Cypress against the additional-tab, multiple-window, and iframe cases; done means the same non-manual tests run reliably under CI for FDC3 and other Desktop Agents.

Written by the indexing model from the issue text.